Brock was waiting to see an eye doctor at the Perryville prison, where she used the bathroom. Someone tattled on Brock to a corrections officer, who gave the write-up to Brock -- who had previously been told not to use that bathroom.

Brock admitted to this, and lost her privileges for 30 days.

She started her 13-year prison sentence in April 2011, and that's still the only infraction to date. In other words, after nearly a year-and-a-half in prison, she's stabbed a grand total of zero people.